Now days, the development of the telecomm networks has entered a cross road. Traditional telecom networks are heavily impacted by new IP networks designed based on the Internet idea increasingly, they are in a process of the essential transformation. During this process, it is gradually realized that the next generational telecom network should take advantage of the IP network using packet-based switch technology and a connectionless operation mode, and take advantage of the technical idea that complex flow control technology should not be used between network devices. And this idea is begun to be practiced.
IP networks are tries to be used to carry telecommunication services in some areas of current telecom networks. Some of them are partly successful. IP telephone services used currently is one typical example. But, telecommunication services have very high requirements for the security and the Quality of Service (hereinafter referred to as “QoS”) themselves. Because Internet, as a representative of existing IP networks, is a kind of network with free, open mechanisms, but without uniform management mechanism. Its design idea is to provide users a free, convenient platform. And the users' work had better not to be disturbed by the networks except that some network access fee needs to be charged to remain networks existence, in that case, network operators take charge of nothing but some management mechanism of users authentication. Therefore, users do not believe that the telecommunications services with high security requirements can be carried over existing Internet without security and trust guarantee. Now, important commercial services networks, even services data of large enterprise networks have not been carried over the public IP networks of the enterprises. On the other hand, there are not heavy problems to provide voice communications services with less quality of service requirements currently over Internet because Internet does not have any management and quality of services guarantee. But once data services and real time video services with high QoS requirements need to be provided, existing Internet can not meet the requirements. This is why some important cases transmitted over networks often need the separate telecom security arrangement provided by the telecom operators.
Because of the questions above, it is noticed that next generation telecom networks can not be realized by migrating telecommunications services to the existing Internet simply. Next generation telecom network will be IP network, but it is an IP Telecom Network which design idea is very different from that of existing IP network based on Internet design idea. (see Jiang Lintao: The research on IP telecommunications technology, <<ZTC Telecom technology>> 2003.1 and The research on next generation telecom network, <<Telecommunications science>>, 2004.1). On the one hand, IP Telecom Network should fully absorb the technical advantages brought by IP network's connectionless character; on the other hand, there is a need to meet the telecommunications services' high requirements to security and quality of service. Though this idea has been brought out for a period of time, there has still not been a technical solution for it until now.